title: Cardiovascular magnetic resonance of scar and ischemia burden early after acute ST elevation and non-ST elevation myocardial infarction.
abstract: BACKGROUND
  The acute coronary syndrome diagnosis includes different classifications of myocardial infarction, which have been shown to differ in their pathology, as well as their early and late prognosis. These differences may relate to the underlying extent of infarction and/or residual myocardial ischemia. The study aim was to compare scar and ischemia mass between acute non-ST elevation myocardial infarction (NSTEMI), ST-elevation MI with Q-wave formation (Q-STEMI) and ST-elevation MI without Q-wave formation (Non-Q STEMI) in-vivo, using cardiovascular magnetic resonance (CMR).
  
  
  RESULTS
  This was a prospective cohort study of twenty five consecutive patients with NSTEMI, 25 patients with thrombolysed Q-STEMI and 25 patients with thrombolysed Non-Q STEMI. Myocardial function (cine imaging), ischemia (adenosine stress first pass myocardial perfusion) and scar (late gadolinium enhancement) were assessed by CMR 2-6 days after presentation and before any invasive revascularisation procedure. All subjects gave written informed consent and ethical committee approval was obtained. Scar mass was highest in Q-STEMI, followed by Non-Q STEMI and NSTEMI (24.1%, 15.2% and 3.8% of LV mass, respectively; p < 0.0001). Ischemia mass showed the reverse trend and was lowest in Q-STEMI, followed by Non-Q STEMI and NSTEMI (6.9%, 14.7% and 19.9% of LV mass, respectively; p = 0.012). The combined mass of scar and ischemia was similar between the three groups (p = 0.17). The ratio of scar to ischemia was 3.5, 1.0 and 0.2 for Q-STEMI, Non-Q STEMI and NSTEMI, respectively.
  
  
  CONCLUSIONS
  Prior to revascularisation, the ratio of scar to ischemia differs between NSTEMI, Non-Q STEMI and Q-STEMI, whilst the combined scar and ischemia mass is similar between these three types of MI. These results provide in-vivo confirmation of the diverse pathophysiology of different types of acute myocardial infarction and may explain their divergent early and late prognosis.
authors.affiliation: Academic Unit of Cardiovascular Medicine, University of Leeds, Leeds, UK. S.Plein@leeds.ac.uk
authors.forename: Sven
authors.initials: S
authors.lastname: Plein
authors.forename: John F
authors.initials: JF
authors.lastname: Younger
authors.forename: Patrick
authors.initials: P
authors.lastname: Sparrow
authors.forename: John P
authors.initials: JP
authors.lastname: Ridgway
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Ball
authors.forename: John P
authors.initials: JP
authors.lastname: Greenwood
mesh_terms: D054058:Acute Coronary Syndrome / Q000473:pathology* / Q000503:physiopathology; D000241:Adenosine; D000368:Aged; D003287:Contrast Media; D003326:Coronary Circulation; D005080:Exercise Test; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology; D017202:Myocardial Ischemia / Q000473:pathology* / Q000503:physiopathology; D055414:Myocardial Perfusion Imaging; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012720:Severity of Illness Index
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA; D000241:Adenosine